The present invention relates to a device for the abrasive machining of cylindrical journals on components, in particular for machining journals and crank pins on crankshafts using abrasive material (an abrasive strip), including, for the purpose of machining each journal, an arm which is mounted so that it can pivot freely about a horizontal pin on a vertically mobile slide and which comprises, on its lower portion, two jaws that can be clamped against one another and carrying means for applying the abrasive against the journal to be machined when the jaws are clamped together.
On known machines for abrasive machining of this type, as marketed, for example, for many years now by the Applicant, with a view to the simultaneous superfinishing of shaft journals and more especially of the journals and crank pins of crankshafts, the two jaws of each arm each comprise two blocks for applying the abrasive strip to the journal to be machined, this application being realized through the clamping effect produced by spring washers fixed to one of the two jaws.
This way of applying the abrasive against the journal to be machined leads to application pressures that are practically uncontrollable and that are not the same on the different application means of each arm.
Furthermore, in the event of the journal for machining being off-centered in relation to the axis of rotation of the workpiece which is rotated about this axis during machining, the arm becomes unbalanced owing to the masses of the arm set in motion when the workpiece is rotated about its axis.
Finally, hitherto, when machining workpieces comprising off-centered journals, it is essential to index the workpiece from the outset, that is to say to position it angularly about its axis of rotation so that the axes of the off-centered journals are located in one and the same vertical plane containing the axis of rotation of the workpiece, before engaging the arm or arms with the workpiece. Indeed, the arms of these known machines cannot position themselves of their own accord on laterally offset off-centered journals.